Soil respiration rate in summer maize field under different soil tillage and straw application

Demanding for food security and current situation of global warming give a high and strict request to North China Plain in food production and inhibition of agricultural carbon emission. To explore the effective way to decrease CO2 emission and remain high grain yield, in 2012 summer maize growing season from a long term project in North China Plain, soil organic carbon, soil CO2-C evolution rate, soil temperature, grain yield, and ratio of soil respiration to grain yield in different soil tillage and straw application treatments were invested. The results showed that in 0-20 cm soil layer, the organic carbon in no tillage was significantly higher than that in conventional tillage. Both in no tillage and conventional tillage, straw application could enhance the soil organic carbon concentrations at ma¬turity. The mean soil CO2-C evolution rate in no tillage was significantly lower than that in conventional tillage; how¬ever, straw application could significantly increase soil CO2-C evolution rate, no matter in no tillage or conventional tillage. This result was mainly due to the changes in soil organic carbon, soil total porosity, and soil temperature. No tillage and straw application result in a significantly increase in grain yield and ratio of soil respiration to grain yield of summer maize. The result obtained in field crop conditions support the idea that both no tillage and straw application affect CO2 emissions in North China Plain

Influencing Factors on Farming System Development in Shandong Province

The developmental situation of the farming system in Shandong Province is introduced. At present, Shandong Province is at the semi-intensive, semi-commercial and semi-sufficiency level of farming system. Eastern coast and central Shandong agricultural zones are moving in the direction of modern farming system, having formed a preliminary new pattern of the coordinated development of grain, feedstuff, economic and other crops. Influencing factors on the development of farming system in Shandong Province is analyzed, which are agricultural production condition and input level, population and food, policy measures, development of natural resources and regions, agricultural industrialization and urbanization level, and scientific and technological level. Total population will be within 1 00 million at the year 2020; per capita annual share of grain will be 475 kilograms; and there is great pressure on grain production. Therefore, we must change the pattern of agricultural development and accelerate the establishment of modern farming system. Agricultural machinery, water conservancy projects, and chemical fertilizer application have greatly affected the development of farming system. Improvement of production conditions has promoted the adjustment of agricultural structure, increased the planting ratio of winter wheat-summer maize, and improved multiple-cropping index. Development of agricultural industrialization has promoted the transfer of rural labor force and the establishment of modern farming system; while the unbalanced development of cities has restricted the establishment of modern farming system. Therefore, the appropriate policy, scientific and rational regional distribution, and advanced science and technology can help to set up the modern farming system in Shandong Province.Shandong Province, Structure adjustment, Regional development, Farming system, China, Agribusiness,

Influencing Factors on Farming System Development in Shandong Province

The developmental situation of the farming system in Shandong Province is introduced. At present, Shandong Province is at the semi-intensive, semi-commercial and semi-sufficiency level of farming system. Eastern coast and central Shandong agricultural zones are moving in the direction of modern farming system, having formed a preliminary new pattern of the coordinated development of grain, feedstuff, economic and other crops. Influencing factors on the development of farming system in Shandong Province is analyzed, which are agricultural production condition and input level, population and food, policy measures, development of natural resources and regions, agricultural industrialization and urbanization level, and scientific and technological level. Total population will be within 1 00 million at the year 2020; per capita annual share of grain will be 475 kilograms; and there is great pressure on grain production. Therefore, we must change the pattern of agricultural development and accelerate the establishment of modern farming system. Agricultural machinery, water conservancy projects, and chemical fertilizer application have greatly affected the development of farming system. Improvement of production conditions has promoted the adjustment of agricultural structure, increased the planting ratio of winter wheat-summer maize, and improved multiple-cropping index. Development of agricultural industrialization has promoted the transfer of rural labor force and the establishment of modern farming system; while the unbalanced development of cities has restricted the establishment of modern farming system. Therefore, the appropriate policy, scientific and rational regional distribution, and advanced science and technology can help to set up the modern farming system in Shandong Province

Responses of photosynthesis, chlorophyll fluorescence, and grain yield of maize to controlled-release urea and irrigation after anthesis

Controlled-release urea (CRU) is a new type of urea, which may increase crop nitrogen (N)-use efficiency compared with conventional urea (CU), but the conditions where it outperforms urea are not well defined. A field experiment assessing responses of plant growth and grain yield of maize to CRU and irrigation was conducted on a typical agricultural farm in Shandong, China. Five treatments of the two types of urea (75, 150kg N ha(-1), 0kg N ha(-1)) were applied as basal fertilizer when sowing maize, and two water treatments (W-0 and W-1) were used 23 d after anthesis. Net photosynthetic rate (P-N) and chlorophyll concentration as well as leaf-area index (LAI) increased significantly by both CRU and CU application, with the increases being larger in CRU-treated plants than in CU-treated plants at grain filling and maturing stages. CRU significantly enhanced the maximum photochemical efficiency (F-v/F-m), PSII coefficient of photochemical fluorescence quenching (q(P)), and actual quantum yield of PSII electron transformation (phi(PSII)) but decreased the nonphotochemical quenching (NPQ). Cob-leaf N concentration of CRU-treated plants was significantly higher than that of CU-treated plants under no irrigation, but not in the irrigation treatment 30 d after anthesis. Significant positive correlations were found between cob-leaf N concentration and P-N both with and without irrigation. Grain yield of maize was significantly higher in the CRU treatment than in the CU treatment under both irrigation conditions. In conclusion, CRU as a basal application appeared to increase the N-use efficiency for maize relative to CU especially by maintaining N supply after anthesis

Climate-Smart Tillage Practices with Straw Return to Sustain Crop Productivity

Climate change seriously threatens global crop production. However, there are few reports on field crop yield and yield components based on long-term different climate conditions. The objectives of this study were to identify and compare the differences in crop yield and yield components in long-term tillage and straw returning under different climate regions. Conventional tillage (CT) and rotary tillage (RT) in combination with no straw return and whole straw return (S) were conducted under a wheat (Triticum aestivum L.)–maize (Zea mays L.) cropping system in cool-wet and warm-dry regions from 2010 to 2019. We hypothesized that long-term suitable tillage under warm-dry or cool-wet regions can increase the yield and components of wheat and maize, and temperature and precipitation had significant effects on crop yield and yield components. Conventional tillage with straw return (CTS) in the warm-dry region and rotary tillage with straw return (RTS) in the cool-wet region can increase the yield and yield components of wheat and maize, respectively, compared with CT. The yield stability of wheat was higher than that of maize under the two climate conditions. Compared with tillage practices, the effects of experimental sites and straw return on crop yield and yield components were more remarkable. The combination of mean temperature, annual precipitation, and yield components explained 75% and 100% of the variance in the wheat yield and maize yield, respectively. The thousand-kernel weight was the key factor in regulating wheat yield, and kernel number was the key factor in regulating maize yield. In conclusion, the combination of rotary tillage in cool-wet regions or conventional tillage in warm-dry regions with straw return is a good technique for increasing crop security

Sensitivities of Physical and Chemical Attributes of Soil Quality to Different Tillage Management

Tillage management is a direct factor in affecting soil quality, which is a key factor in sustainable agriculture. However soil quality evaluation needs significant manpower, material resources and time. To explore the sensitive indicators of soil quality affected by tillage management, eight soil physical and chemical properties under three tillage managements, including plow tillage, subsoiling tillage and rotary tillage, were determined under a long-term experiment in North China Plain. The results showed that subsoiling tillage management had the highest soil organic carbon and total nitrogen in the 0–20 cm layer and the lowest soil bulk density in the 30–40 cm layer. Rotary tillage management had the highest soil water content in the 0–40 cm layer. Meanwhile, compared to 2002, the soil organic carbon, total nitrogen and soil bulk density had varied greatly in 2012, but there was no significant difference between 2012 and 2018. However, other property concentrations tended to increase in 2002, 2012 and 2018. In addition, there was a significant linear relationship between soil quality index and grain yield. Subsoiling tillage management had the highest soil quality index and gain yield both in 2012 and 2018. The soil quality can be evaluated through the sensitive indicator of soil organic carbon, total nitrogen, soil bulk density, total phosphorus and soil water content, which provides a scientific basis for selecting reasonable tillage management and evaluating soil quality in this agricultural production area or other similar areas

Low Light Increases the Abundance of Light Reaction Proteins: Proteomics Analysis of Maize (<i>Zea mays</i> L.) Grown at High Planting Density

Maize (Zea mays L.) is usually planted at high density, so most of its leaves grow in low light. Certain morphological and physiological traits improve leaf photosynthetic capacity under low light, but how light absorption, transmission, and transport respond at the proteomic level remains unclear. Here, we used tandem mass tag (TMT) quantitative proteomics to investigate maize photosynthesis-related proteins under low light due to dense planting, finding increased levels of proteins related to photosystem II (PSII), PSI, and cytochrome b6f. These increases likely promote intersystem electron transport and increased PSI end electron acceptor abundance. OJIP transient curves revealed increases in some fluorescence parameters under low light: quantum yield for electron transport (φEo), probability that an electron moves beyond the primary acceptor QA− (ψo), efficiency/probability of electron transfer from intersystem electron carriers to reduction end electron acceptors at the PSI acceptor side (δRo), quantum yield for reduction of end electron acceptors at the PSI acceptor side (φRo), and overall performance up to the PSI end electron acceptors (PItotal). Thus, densely planted maize shows elevated light utilization through increased electron transport efficiency, which promotes coordination between PSII and PSI, as reflected by higher apparent quantum efficiency (AQE), lower light compensation point (LCP), and lower dark respiration rate (Rd)

Coupling effects of urea types and subsoiling on nitrogen–water use and yield ofdifferent varieties of maize in northern China

Increasing nitrogen and water use efficiencies is most important for the agricultural sustainable development in China, especially in northern China. This paper mainly studied the coupling effects of controlled-release urea and subsoiling on nitrogen and water use efficiency, and yield. The experiment adopted a split-split plot design. Main plots were varieties, including Zhengdan 958 (Z) and Denghai 3 (D). Subplots consisted of two tillage methods: rototilling for stubble breaking (R), and subsoiling after rototilling for stubble breaking (S). Sub-subplots were N regimes: conventional urea (U), controlled-release urea (C) with the amount of 225 kg N/ha, and non-N as the control. The nitrate reductase, grain quality and straw yield, soil nitrate, and nitrogen and water use efficiency were evaluated. The results showed that, the soil nitrate content of the treatment that applied the controlled-release urea at the spike formation stage is lower than the conventional urea; however, after flowering, the soil nitrate content of the treatment that applied the controlled-release urea was significantly higher than that of the conventional urea. And the treatment that applied the controlled-release urea increased the N uptake of the aboveground portion and water use efficiency of the maize. And the treatment with subsoiling maintained a high level of nitrate reductase under the same maize varieties and urea type conditions, boosted the N uptake of the aboveground portion, and increase the water use and the biomass yield. Furthermore, under the same tillage and urea type, the biomass production of Denghai 3 was higher than Zhengdan 958. The results showed that there were significant coupling effects of urea types and subsoiling on nitrogen-water use and yield of different varieties of maize. Selecting suitable varieties and using controlled-release urea combined with subsoiling can improve the efficiency of water and nitrogen use efficiency and increase the grain yield in northern China. (C) 2012 Elsevier B.V. All rights reserved